Reverts twbs/bootstrap#33621.
Rather than go through the motions of splitting our grid, no generating some classes, or generating different classes in different places, I'm proposing we revert this outright and address it properly when we can devote the time to it. Right now this breaks too many things and I'm not sure what the best solution is just yet.
Fixes #34611 (closed), fixes #34564 (closed), fixes #34335 (closed), fixes #34363 (closed).